Crank shaft for internal-combustion engines



May 11 1926. 1,584,279

F S. DUESENBERG CRANK SHAFT FOR INTERNAL COMBUSTION ENGINES Original Filed b 11. 1921 2 Sheets-Sheet 1 May 11 1926. I 1,584,279

F. S.'DU ESENBERG CRANK SHAFT FOR INTERNAL COMBUSTION ENGINES Original Filed 11. 1921 2 Sheets-Sheet 2 9 5 MW M Patented May 11, 1926.

UNITED, STATES "rnnnnnrcx s. nunsnnnnne,

( 1,584,279 PATENT OFFICE.

01 INDIANAPOLIS, INDIANA.

. GRANK'SHAFT FOR INTERNAL-COMBUSTION ENGINE Original ammonia February 11, 1921, Serial N 444,082. Divided and this application filed p March 5,1923. Serial No. 622,785. 1

Thisinvention relates to. a novel and improved crank-shaft for eight--cylinder 1nternal combustion engines, the aim being to secure an engine characterized by light weight, economy in the use of fuel, slmplicltyv of construction, and accessibility.

- The invention will be best understood by reference to the following description, when takenin connection with the accompanying drawings of .one illustrative embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is a vertical, longitudinal, sectional viewof an internal combustion engine provided with aerank-shaft exemplifying my invention; and

Fig. 2 is a somewhat conventionalized perspective view of the crank-shaft, with the so-called crank-pin collars and their counterbalances omitted.

Referring to the drawings, and to the embodiment of the invention which is selected for exemplification, and having reference first to Fig.1, there is shown an internal combustion engine having eight cylinders A, which for convenience of'description will be referred to as A to A inclusive, because of the fact that it is customary in the art to refer to the cylinder at the front of the engine as the No. 1 c linder, and to the second as the No. 2, an so on. The cylinders are formed as a single casting, or to use a common expression in the art, they are cast in a block. The cylinders are disposed with their axes in a single plane, herein vertical,that is to say, the cylinders are upright and in a single row, as distinguished from V-type engines. Working in the cylinder are 'istons B, connected by connecting rods to crank-pins D of a crank-shaft of novel construction, which is housed in a crank-case 9. For convenience of description, the several pistons, connecting rods and crankins will be referred to b the letters B, and D, accompanied by tlie numerals corresponding to the cylinders. In thepresent example, the latter are provided with aremovable cylinder head 10 presenting combustion chambers for the several cylinders. The admission of the combustible mixture to the chambers, the ignition thereof, and the release ofv the exhaust gases, may be efiected by any usual valve mechanism and ignition apparatus, which,

however, need not be described herein, since it forms no necessary'part of the present invention.

The crank-shaft is mounted, in three bearings, namely: two end bearings 11 and 12, and an intermediate bearing 13, usually called a center'bearing; The use of this short, is not subject to the distortion and whipping action, with the accompanying vibration, which has heretofore character-- ized eight-cylinder engines in which the cylinders are disposed in a single row.

The crank-shaft which is of novel form W1ll I10W be described, reference being had part cularly to Fig. 2. The crank-shaft is provided with two end bearing portions 14 and 15, and an intermediate or center bearmg portion 16 mounted in the bearings 11, 12 and 13, respectively. The crank-shaft may be considered as bein made up of two similar units or groups 0 crank-pins, each comprising four pins whose axes are in a plane perpendicular to the plane of the axes of the pins of the other group. Thus the axesof the crank-pins D D D and D,

will lie in a plane perpendicular to the plane containing the axes of the crank-pins D D, D and D One of these groups is disposed between the front and intermediate bearing, and the other between the latter and the rear bearing.

It should here be observed that in each group there are two contiguous crank-pins Whose axes are in alignment and in the same radial plane,--or to state it differently, one of these crank-pins may be regarded as an axial prolongation of the other. This applies to the crank-pins D? and D of one group, and to the crank-pins D and D of the other.

The crank-shaft comprises four short crank-arms 17, 18, 19 and 20, and four long crank-arms 21, 22, 23 and 24. Each of the short crank-arms connects the crank-pin to a main bearing portion, while each of the lon crank-arms extends across the main axis 0 the crank-shaft and directly connects one crankin to another, without the interposition 0 a main bearing portion.

Preferably, 1 the crank-shaft is suitably counterweighted. In the case of the short crank-arms 17, 18, 19 and 20, there are provided counterweights 25, 26, 27 and 28, the weight of each of which is substantially equal to the weight of its corresponding crank-arm, not including the crank-pin. It should. here be observed that the crank-pin D is in balance with the crank-pin D", and that the crank-pin D is in balance with the crank-pin D Likewise in the other group, the crank-pin D is in balance with the crank-pin D, and the crank-pin D 1s 1n balance with the crank-pin D. This does not take into account. the two masses of metal, one intermediate thecrank-pms D and D and the other'intermediate the crank-pins D and D". These are counterbalanced b weights 29 and 30, which are formed on ong arms 31 and 32, respectively, each extending from its pair of crank-pins across the main axis of the crank-shaft.

.Thus it is evident that by this simple and convenient arrangement of the bearings, crank-pins and counterweights, there is provided a crank-shaft which can easil be placedin staticand running balance. referably, the thickness of the crank cheeks and the diameters of the main bearings'increase from the front toward the rear end of the crank-shaft,'that is to say, the thickthe crank-arm 19, while the diameter of the main bearingxportion 16 is greater than that of the .main aring portion 14, and in turn -the diameter of the main bearing, portion 15 is greater than that of the main bearing portion 16. This is helpful in avoiding torsional vibration in the crank-shaft. In practice, it is found that an engine embodying the described construction operates with such a minimum of vibration that it is capable of running at speeds far in excess of any other type of which I am aware, and

.thus an engine of high power and low weight is produced.

This a plication is a division of my pending application, Ser. No. 444,082, filed February 11,1921.

Having thus described one embodiment of my invention, but without limiting myself thereto, what I claim and desire by Letters Patent to secure is:

1. A crank-shaft havin eight crank-pins arranged in two groups 0 four, a plane containing the axes of the crank-pins of one group being perpendicular to a plane containing the axes of the crank-plus of the other group, and three main bearing por tions only, one at each end and one intermediate said groups, the thickness of the crank cheeks increasing from one end of the crank-shaft toward the other.

2. A crank-shaft having eight crankins arranged in two groups of four, a. p ane containing the axes of the crank-plns of one group being perpendicular to a lane containing the axes of the crank-plns of the other group, and three main bearing portions only, one at each end and one intermediate said groups, the diameters of the main bearing portions increasin from one end of the crank-shaft toward t e other.

3. A crank-shaft having eight crank-pins arranged in two groups of four, a plane containing the axes of the crank-pins of one group being perpendicular to a plane containing the axes of the crank-pins of the other group, and three mainbearing portions only, one at each end and one intermediate, said groups, the thickness of the crank-cheeks increasing from one end of the crank-shaft toward the other, and the diameters of the mainbearing portions increasing from one end of the crank-shaft toward the other.

4. A crank-shaft having eight crank-pins arranged in two groups of four, a plane containing the axes of the crank-pins of one group being perpendicular to a plane containing the axes of the crank-pins of the other group, and three main bearing portions only, one at each end and one intermediate said groups, the thickness of crankarms adjacent one end of the crank-shaft being greater than the thickness of crankarms adjacent the other end, and the diameter of the main bearing portion at one end being greater than the diameter of the main bearing portion at the other end.

In testimony whereof, I have signed my name to this specification FREDERICK s. DUESENBEBG. 

